Oo no Suefumi was a dancer who performed the Sairyou-oh dance, a ritual dedicated to the western warrior Kyougi, known for wearing a terrifying mask in battle. Seven years before the main events, he collapsed and died during a performance before the imperial family. His death spawned rumors that any dancer performing this dance would meet a similar fate.

In the present, he manifests as a mysterious young man suffering from amnesia. He encounters the protagonist during a rainstorm and lends her his coat. Later, at an abandoned shack, he listens to her doubts about her duties and gives her a mask in his possession. This mask is subsequently identified as one used for the Sairyou-oh dance.

Investigations reveal his true identity as Oo no Suefumi, existing as a vengeful spirit threatening the annual purification dance at the imperial palace. His spiritual presence causes significant defilement, resulting in illness among the nobility and endangering the capital. When confronted, he loses his remnant humanity to undead malice, wounds the protagonist, and engages her guardians in battle. During this confrontation, he transforms into a hostile entity with hellish pupils.

The protagonist ultimately purifies his soul by sealing him during his final performance of the Sairyou-oh dance. She pleads for him to accept the afterlife and his passion for dancing, leading him to depart peacefully. After his purification, she recalls his inherent kindness and that his spirit found peace.

Suefumi appears in related media, such as the visual novel adaptation of the Maihitoyo story, where his role follows the same narrative arc involving his past as a dancer, his ghostly return, and eventual purification. His character design includes a distinctive beauty mark with narrative significance.

Within the broader franchise, his story represents a self-contained tragedy centered on unresolved passion and spiritual redemption, without direct ties to other plotlines like the Demon Clan conflicts.